1. Field of the Invention
Aspects of the present invention relate to an image forming apparatus, a chip, and a chip package.
2. Description of the Related Art
Currently, integrated circuits, such as semiconductor memory circuits, are getting smaller in size, while having higher performance. The effect of a package structure on such integrated circuits is becoming more important. In particular, a technique of effectively arranging and routing pads greatly affects the performance of integrated circuits.
A conventional integrated circuit was free from a limitation on the chip size, and thus, much effort was not required to design the chip package structure, so as to ensure high performance. In other words, it was easy to insure that bonding wires and pads in a conventional chip package had sufficient separation distances.
However, as chips have become smaller, gaps between neighboring gates and bonding wires have become narrower. Also, as the clock frequency of chips becomes higher, a higher level of cross-talk can occur between signals transmitted through the pads, due to the close proximity of the pads and bonding wires. Cross-talk refers to a signal induced phenomenon that occurs among neighboring nets, that is, a co-signal interference phenomenon.
Cross-talk is a serious problem among different signal types, such as between data signals and address signals, and between data signals and control signals. This is because cross-talk occurring in one signal type induces cross-talk in other signal types.
FIG. 5 shows a simulation wave diagram illustrating the effect of cross-talk in a conventional chip package. Referring to FIG. 5, a data signal and an address signal, which are transmitted in close proximity to each other, have different frequencies and different phases. Accordingly, the address signal may change when the data signal maintains a predetermined electric potential, and the change in the address signal induces a change in the neighboring data signal, thereby causing cross-talk.
In order to prevent cross-talk, pads and bonding wires of a package should be designed to have sufficient separation distances from one another. However, as the degree of integration of chips becomes higher, it is difficult to ensure sufficient separation distances. Therefore, there is a demand for a chip package that is designed to prevent cross-talk, while maintaining a high degree of integration.